Cryoprobe with reduced adhesion to frozen tisssue

Abstract

The present invention relates to devices and methods for cryosurgery. More particularly, the present invention relates to a cryoprobe which does not form strong adhesive or mechanical bonds with body tissues when such tissues are frozen by cooling action of the probe. Embodiments of the present invention include a cryoprobe having a distal cooling module with an outer surface layer of non-polar molecules, a probe having a distal cooling module with a microscopically smooth outer surface, a cryoprobe comprising a mechanism for coating a distal cooling module thereof with non-polar lubricant during movement of the cryoprobe within body tissues of a patient, and a non-cooling cryosurgery probe with non-adhesive features. Also presented are methods utilizing disclosed cryoprobes to facilitate cryosurgery and to enhance accuracy of cryoablation of user-selected cryoablation targets.

Description

FIELD AND BACKGROUND OF THE INVENTION[0001]The present invention relates to devices and methods for cryosurgery. More particularly, the present invention relates to a cryosurgical probe to which body tissues do not tend to adhere strongly when frozen by cooling action of the probe. Embodiments of the present invention include a cryoprobe having a cooling module with an outer surface layer of non-polar molecules, a cryoprobe having a cooling module with a microscopically smooth outer surface, a cryoprobe comprising a mechanism for coating a cooling module thereof with non-polar lubricant during movement of the cryoprobe within body tissues of a patient, and a non-cooling probe for use in a cryosurgery context and having non-adhesive surface features. Also presented are methods utilizing such probes to facilitate cryosurgery and to enhance accuracy of cryoablation of a user-selected cryoablation target.[0002]In an increasingly popular therapeutic technique, cryoprobes are used to abla...

AI Technical Summary

Benefits of technology

Enables rapid and safe movement and removal of cryoprobes within the body, reducing tissue damage and shortening surgical time by minimizing adhesion to frozen tissues, while maintaining effective cooling capabilities.

Problems solved by technology

One issue complicating use of cryoprobes is a tendency of body tissues to adhere to cryoprobes when those tissues freeze during cryosurgery.

In current practice according to methods of prior art, once an inserted cryoprobe is used to cool tissue and that cooled tissue freezes, the inserted cryoprobe cannot be displaced within the patient's body nor removed from that body, because the probe, firmly adhering to the body tissues, cannot be moved without tearing those tissues, if it can be moved at all.

Rapid removal of cryoprobes from a body following cryosurgery is a practical requirement of most cryosurgical interventions, since waiting around for tissues to naturally thaw at the end of an intervention is not an efficient use of time for a busy surgeon.

In some surgical contexts adherence of tissues to cryoprobes can be dangerous as well as merely inconvenient.

Adherence of delicate and vulnerable tissues to a cryoprobe held in the hands of a surgeon can constitute a significant danger in certain surgical interventions, because delicate adhering tissues can inadvertently be torn or otherwise mechanically damaged.

Adherence of moving tissues (e.g. heart muscle) to a hand-held or mechanically immobilized cryoprobe can cause mechanical damage to tissues as well.

However, as thawing begins and portions of frozen heart muscle in proximity to an adhering treating cryoprobe begin to thaw and to beat, residual adhesion of cryoprobe to tissue at that time can cause tearing of delicate heart tissue or delicate blood vessel tissue of the pulmonary vein ostium.

Heated thawing is often considered a necessary part of the cryoablation process, yet in discussions comparing the therapeutic advantages and disadvantages of natural thawing as opposed to heating thawing, the disadvantage of natural thawing most often cited is the long delays required before inserted cryoprobes can be moved or removed, when natural thawing is used.

Equipping cryoprobes with heating mechanisms adds to the complexity and cost of cryosurgical systems, and adds also to the complexity of operating procedures using those probes.

Heating probes prior to moving them can also be somewhat time-consuming.

However, it is a disadvantage of use of such probes that once tissues around them are frozen, adherence of tissues to probe prevents movement of the probe, thereby preventing displacement of the probe during cryotherapy and also preventing easy and rapid removal of the probe subsequent to completion of cryosurgery prior to thawing of the iceball formed during cryotherapy.

Probes which are not themselves cryoprobes yet which are used during cryotherapy procedures, and particularly probes containing only thermal sensors, are typically of thin and simple construction and are typically not equipped to provide heat.

Littrup does not teach or suggest use of such a coating to enable or facilitate displacement within or removal of such a probe from frozen tissue, and provides no implementation details.

Cryoprobes known to prior art have external surfaces which, though they appear smooth to the naked eye, are not in fact smooth on a microscopic (e.g. nanometer) scale, and which therefore present geometrically complex surfaces such as concavities (at the microscopic level) within which ice crystals may form and from which those ice crystals cannot easily be dislodged.

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